Liquid Crystal Display Common Voltage Compensation
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Solution Overview
Problem
Liquid crystal display devices face issues with compensating deviations in common voltage distortions between the center and periphery of the common electrode, leading to image instability due to parasitic capacitance and varying load characteristics.
Innovation Solution
A liquid crystal display device with a common voltage compensating unit that generates and supplies compensating signals to respective regions of the common electrode, using feedback from these regions to correct distortions, thereby reducing ripple and maintaining a stable common voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a common voltage compensating unit is provided to eliminate cross talk, then cross talk is reduced, but compensating deviation between center and periphery regions cannot be overcome
Solution Approach 1:
The common electrode is divided into multiple regions (center region and periphery region), and separate compensating signals are generated for each region. This segmentation allows independent compensation of voltage distortions in different areas, resolving the contradiction by enabling both cross talk elimination and uniform image quality across the display panel.
Solution Approach 2:
Different compensating signals with distinct characteristics are applied to different regions of the common electrode. The center region receives a compensating signal optimized for its load characteristics, while the periphery region receives a different compensating signal suited to its characteristics. This local quality approach ensures that each region's specific distortion issues are addressed, achieving both cross talk reduction and uniform image stability.
2Object-affected harmful factors
If a single compensating signal is supplied to the common electrode, then cross talk is eliminated, but distortion variation between center and periphery cannot be corrected
Solution Approach 1:
The compensating signal generation is segmented into multiple independent pathways, one for the center region and another for the periphery region. Each pathway processes feedback from its respective region and generates an optimized compensating signal, thereby achieving precise voltage uniformity across different areas while eliminating cross talk.
Solution Approach 2:
The system applies the principle of local quality by tailoring the compensating signal characteristics to match the specific electrical characteristics of each region. The center region compensating signal accounts for different load characteristics compared to the periphery region, ensuring precise voltage control and uniformity across the entire common electrode.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively reduces compensating deviations between the central and peripheral regions of the common electrode, ensuring a stable image by eliminating distortions caused by parasitic capacitance and load variations.
Implementation Method 1
A parasitic capacitance is formed between the common electrode of the color filter substrate and the data lines of the thin film transistor substrate. When a data signal value between the data lines changes sharply, the parasitic capacitance causes a ripple at the common voltage Vcom supplied to the common electrode.
Implementation Method 2
The orientation of the liquid crystal molecules is controlled by controlling an electric field between the two substrates of the liquid crystal display panel.
Data Source
AI summary
A liquid crystal display device and method for driving the same is described for reducing a compensating deviation of a common voltage. The liquid crystal display device includes a liquid crystal display panel; a data driver for driving data lines of the liquid crystal display panel; a gate driver for driving gate lines of the liquid crystal display panel; and a common voltage compensating unit for generating a plurality of compensating signals for compensating respective distortions of common voltages at a plurality of common regions of a common electrode of the liquid crystal display panel by using common voltages fed back from the common regions, and supplying compensating signals corresponding to each of the plurality of common regions.